1. Field of the invention
This invention relates to an optical system such as retinal camera, and particularly the objective lens thereof, for observing or photographing therethrough the fundus.
2. Description of the Prior Art
A lens having a wide angle of view which can form an image of a wide range of the fundus is desired as the objective lens of a retinal camera. However, since the reflection factor of the fundus is originally small, the reflected light on each surface of the lens must be sufficiently eliminated and it has been very difficult to construct a lens having a wide angle of view and yet having an excellent image forming performance. Various wide angle objective lenses of such type have heretofore been proposed but their angle of view has only been 45.degree. to 50.degree. at best.